<?php 

header("Content-type: text/html; charset=utf-8");

$num1=20;
$num2 = 30;
$num3 = 50;

echo Sum($num1,$num2);


function Sum($num1 ,$num2)
{
	$num1++;
	$num2++;
	global $num3;
	return $num1+$num2+$num3;
}




 ?>